The Cost Impact of Psoriatic Arthritis Therapy

The limited real world data available for psoriatic arthritis (PsA) patients who receive anti-tumor necrosis factor alpha (anti-TNFα) biologic therapy sparked a recent study on treatment patterns and the cost of therapy in the United States.

About 30% of patients with psoriasis end up developing PsA, and the estimated prevalence in the overall population is between 0.10 and 0.25%, according to the study. Current treatment guidelines offer no guidance as far as the sequence of anti-TNFα biologic therapy that PsA patients should take, the researchers wrote.

For the study, investigators used the Truven Health Analytics MarketScan Research observational claims database to select 990 PsA patients (aged ≥18 years) who started anti-TNFα biologic therapy between October 1, 2009 and September 30, 2010. Patients were required to be continuously enrolled with pharmacy and medical benefits 6 months prior to the index data and through the 3-year follow-up period.

There were 4 key outcomes of interest associated with anti-TNFα biologic therapy: number of patients per line of therapy; time to treatment medication; duration of treatment; and costs associated with treatment.

There were 881 patients on first-line therapy, 72 on second-line, and 37 on third-line or greater. During the 3-month follow-up, researchers observed persistence, time-to-switch or modification, and pharmacy and medical costs measured per patient per month (PPPM).

PsA patients who received only 1 line of anti-TNFα biologic therapy stayed on their therapy for 17.4 months (mean [SD]; 522.3 [418.9] days). Patients who switched to second-line, third-line or greater stayed on first-line for 11.6 months (348.5 [308.7] days) or 10.8 months (325.2 [239.9] days), respectively.

For patients who received 2 lines of anti-TNFα therapy, the time to first treatment modification for first-line therapy was shortest, followed by patients who received 1 line of therapy and those who had 3 or more lines of therapy. Patients who received 3 or more lines of therapy during the follow-up period showed that the time to switch and time to first treatment modification was progressively shorter with each new line of therapy.

The time from first modification of therapy to treatment switch was longer for patients who switched to a second line of therapy compared with those who switched to third-line or greater line of therapy. In terms of medical costs for treatment, the PPPM medical costs were higher for patients who didn’t switch ($322) compared with those who switched to second-line ($167), third-line ($217) or greater line of therapy.

Overall, the findings showed the PPPM pharmacy costs were higher for patients who had 3 or more lines of therapy ($2539) compared with those who didn’t switch ($1985) or switched to a second-line of therapy ($2045). Treatment and cost patterns were found to differ depending on how many times a patient switched anti-TNFα biologic therapy.

A majority of the patients received only 1 line of therapy over the 3-year study period, but a subset of patients did switch to multiple lines of therapy during the follow-up period. The rate of treatment modification overall was found to be low in patients who stayed on first-line therapy and had the lowest rate of modification.

In patients who received at least 3 lines of therapy, the time to switch and the time to first treatment modification was progressively shorter. Overall, medical costs were found to be highest for patients who didn’t switch therapy.

The highest PPPM pharmacy costs increased when patients switched to new lines of therapy. The authors concluded their findings provide a better understanding of real-world treatment patterns, as well as the economic impact of PsA.